I hear that cornhole is popular in Cincinnati. What is it?

Frankly I never got the cornhole thing, but cmariaschiefer explained it about as well as anyone could. I've only watched the game played, and it seems fun.

It's kind of like a bean bag toss with corn in your bags instead of beans. I'm sure there's got to be some history behind it, but I have no idea what it is.

You're right--cornhole is extremely popular in and around Cincinnati (as well as most of Kentucky and Indiana)! It's sort of a strange activity when you play for the first time, but it's a lot of fun. Essentially, you have two elevated wooden boxes, or platforms, with a small hole near the top. The objective is to toss your 'corn bag' into the hole. Generally, contestants compete (either individually or as teams) up to 21 points, with 3 points for every corn bag in the hole, and 1 point for every corn bag on the board. It's pretty popular at graduation parties, birthday parties, and really any sort of outdoor get-together.